DE102015217873A1 - Articles, in particular an air spring bellows, a metal-rubber element or a vibration damper - Google Patents

Abstract

The invention relates to an article having a base body with elastic properties, in particular an air spring bellows, a metal-rubber element or a vibration damper. The article has a monolayer or multilayer main body, wherein the outer layer C is at least two layers C1 / C2 and each layer is formed in each case from an elastomer mixture and wherein in this outer layer at least one layer D of a woven or knitted fabric is embedded. This leads to a further optimization of the fire retardant properties.

Description

The invention relates to an article having a base body with elastic properties, in particular an air spring bellows, a metal-rubber element or a vibration damper.

Articles having elastic properties used for suspension of, for example, motor vehicles or rail vehicles and / or for vibration damping are manufactured using elastomeric mixtures, also referred to as rubber compounds. These elastomeric blends commonly used for the basic properties of such articles are well known. Articles having excellent elastic properties, such as metal-rubber elements or vibration dampers, preferably contain vulcanized rubber compounds predominantly based on natural rubber (NR) and / or polyisoprene rubber (IR). Articles having very good weathering, mineral oil and heat resistance, such as air spring bellows, preferably contain vulcanized rubber compounds predominantly based on chloroprene rubber (CR).

However, articles with these elastomeric mixtures show significant disadvantages in the fire behavior. In case of fire, dense flue gases are produced. In the combustion process of said elastomeric mixtures, which are predominantly based on NR and / or IR, the heat release rate is particularly high. In the combustion process of the elastomeric mixtures, which are predominantly based on CR, the resulting flue gas is toxic to humans and animals.

Due to the increased requirements in recent years in terms of fire protection, which is mainly in the tightened fire safety standard EN 45545 shows, there is an increased demand for fire-optimized polymer articles. These fire protection requirements, both the said elastomeric mixtures, which are based predominantly on NR and / or IR, especially due to the required maximum heat release rate, and the flame-retardant elastomeric mixtures, which are based mainly on CR, especially due to the required smoke toxicity, no longer meet , Thus, the articles containing these elastomeric blends alone generally no longer meet the stringent requirements.

A common method to improve the fire behavior of rubber compounds is the direct incorporation of fire-retardant substances. However, in the case of the articles concerned, this measure generally leads to a significant deterioration in the physical properties, in particular the suspension, setting or vibration properties.

Also fire protection coatings, as in WO 2014/019008 A1 or in EP 2196492 B1 are described are only partially suitable to ensure a lasting fire protection of the article. On the one hand this shows a low tensile strength which has a negative effect on the resistance, on the other hand, these coatings dissolve relatively quickly from the article, especially under dynamic load again. Due to the possibly necessary second vulcanization process in the production of the end products, in particular in the production of injection items such as metal-rubber elements, especially the tear propagation resistance of the mixture of the body due to the usual tendency to reversion in particular of mixtures based on BR, reduced.

Furthermore, the in WO 2014/019008 A1 described fire-resistant coatings, especially at higher temperatures (> 70 ° C) insufficient DVR values. At the same time, the fire protection layer must be comparatively thick in order to ensure adequate fire protection. In the EP 2196492 B1 On the other hand, the described fire protection measure shows a delayed start of the fire protection effect due to the comparatively high onset temperature of the expandable graphites used there.

The object of the invention is now to provide an article which is characterized by an optimized fire protection behavior to meet the more stringent requirements, in particular those in EN 45545 described to fulfill. At the same time, the necessary physical properties of the article should remain at a comparable level and the complexity in the production process should not be appreciably increased.

This object is achieved in that the article has a single or multilayer elastic body, wherein the outer layer C consists at least of a first layer C1 and another layer C2 and each layer is formed in each case from an elastomer mixture and wherein in this outer layer C is embedded at least one layer D of a woven or knitted fabric or knitted fabric between the first layer C1 and the further layer C2.

The following constructions of the article are possible according to the invention:

Version 1:

In a preferred embodiment, the base body is formed in a single layer, so that the layer D of a woven or knitted fabric is embedded in the single layer C, which is at least two layers C1 / C2 and each layer is formed from an elastomer mixture.

The result is the following layer structure: C1, D, C2.

The individual layers are explained in more detail below.

Variant 2:

In a particularly preferred embodiment, the base body is formed in multiple layers. The first layer A is the so-called "inner cap", which is composed of an elastomer mixture. This is followed by a second layer B, which is formed from at least one strength carrier. This is followed by the outer layer C, which is at least two layers C1 / C2 and each layer is formed in each case from an elastomer mixture, in which at least one layer D of a woven or knitted fabric is embedded.

The result is the following layer structure: A, B, C1, D, C2.

The individual layers are explained in more detail below.

Variant 3:

In a very particularly preferred embodiment, the base body is formed in multiple layers. The first layer A is the so-called "inner cap", which is composed of an elastomer mixture. This is followed by a second layer B, which is formed from at least one strength carrier. This is followed by the outer layer C, which is at least two layers C1 / C2 and each layer is formed in each case from an elastomer mixture, in which at least one layer D of a woven or knitted fabric is embedded. In addition, on the layer D of a woven or knitted fabric or knit, which is embedded in the outer layer C, another layer E on the basis of at least one thermoplastic, preferably in the form of a film may be located. The layer D of a woven, knitted or knitted fabric and the layer E based on a thermoplastic are thus both embedded in the outer layer C. The result is the following layer structure: A, B, C1, D, E, C2.

The individual layers are explained in more detail below.

Variant 4:

In a further very particularly preferred embodiment, the main body is formed in a multi-layered manner. The first layer A is the so-called "inner cap", which is composed of an elastomer mixture. This is followed by a second layer B, which is formed from at least one strength carrier. This is followed by the outer layer C, which is at least two layers C1 / C2 and each layer is formed in each case from an elastomer mixture, in which at least one layer D of a woven or knitted fabric is embedded. In addition, a layer G of a woven, knitted or knitted fabric can still be located on this outer layer C.

The result is the following layer structure: A, B, C1, D, C2, G.

The individual layers are explained in more detail below.

Variant 5:

In a further very particularly preferred embodiment, the main body is formed in a multi-layered manner. The first layer A is the so-called "inner cap", which is composed of an elastomer mixture. This is followed by a second layer B, which is formed from at least one strength carrier. This is followed by the outer layer C, which is at least two layers C1 / C2 and each layer is formed in each case from an elastomer mixture, in which at least one layer D of a woven or knitted fabric is embedded. On the layer D of a woven or knitted fabric or knitted fabric, which is embedded in the outer layer C, there is a further layer E based on at least one thermoplastic, preferably in the form of a film. The layer D of a woven, knitted or knitted fabric and the layer E based on a thermoplastic are thus both embedded in the outer layer C of an elastomeric mixture. In addition, a layer G of a woven, knitted or knitted fabric can still be located on this outer layer C.

The result is the following layer structure: A, B, C1, D, E, C2, G. The individual layers are explained in more detail below.

The layers A, B and C form the main body of the article, wherein the layer C consists of at least two layers C1 and C2.

Layer A

The first layer A is the so-called "inner cap", which consists of an elastomer mixture constructed and has particularly good elastic properties. The elastomer mixture is a vulcanizable, preferably thermoplastic-free, rubber mixture containing at least one rubber component as well as further mixing ingredients. Rubber components which may be mentioned in particular are: ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), nitrile rubber (NBR), (partially) hydrogenated nitrile rubber (HNBR), fluorinated rubber (FKM), chloroprene rubber. Rubber (CR), Natural Rubber (NR), Styrene Butadiene Rubber (SBR), Isoprene Rubber (IR), Butyl Rubber (IIR), Bromobutyl Rubber (BIIR), Chlorobutyl Rubber (CIIR), Brominated Copolymer of Isobutylene and Paramethylstyrene (BIMS) , Butadiene rubber (BR), chlorinated polyethylene (CM), chlorosulfonated polyethylene (CSM), alkylated chlorosulfonated polyethylene (ACSM), polyepichlorohydrin (ECO), terpolymers of ECO with ethylene oxide and unsaturated monomers (ETER), ethylene-vinyl acetate rubber ( EVA), acrylate rubber (ACM), ethylene acrylate rubber (AEM), silicone rubber (MQ, VMQ, PVMQ, FVMQ), fluorinated methyl silicone rubber (MFQ), perfluorinated propylene rubber (FFPM), perfluorocarbon rubber (FFKM) , Polyurethane (PU). The aforementioned types of rubber may be unblended. The use of a waste is possible.

Which type of rubber is preferred depends on the type of article. The usual compounding ingredients include at least one crosslinker or crosslinker system (crosslinker and accelerator). Additional compounding ingredients are usually still a filler and / or a processing aid and / or a plasticizer and / or an aging inhibitor and optionally further additives (for example color pigments, reinforcing fibers.

In this regard, reference is made to the general state of rubber mixing technology.

Layer B

The second layer B is formed from at least one strength carrier. This is preferably a cord fabric of one or more layers, preferably of two layers, which have good adhesion to the layer A.

The layer B forms the so-called scaffold. As materials for the layer B, all known synthetic and natural materials may be used alone or in combination, i. as a hybrid fabric.

Synthetic materials are in particular synthetic polymers, such as polyacrylonitrile, polypropylene, polyester, polyamide, polyurethane, polyphenylene sulfide, polyoxadiazole, aramids, such as p-aramid, m-aramid or co-poly para aramid, polyimide, polyetherimide, polyetheretherketone, polyethylene 2,6-naphthalate, polyphenylene, polyphenylene oxide, polyphenylene sulfide, polyphenylene ethers, polybenzoxazoles, polyvinyl alcohol in question. The natural materials may be rock wool or asbestos, or cotton, flax or hemp, or wool or silk. Inorganic materials such as glass, ceramics, carbon (carbon), metal, such as steel, or rock, such as basalt, are also conceivable.

Preferably, it is polyamide, in particular PA6.6, or polyester alone or in combination.

To obtain a sufficient Konfektionsklebrigkeit during the manufacturing process of the article, the cord fabric may be rubberized or frictional on one side or on both sides. For gumming it is preferred to use either a composition which is quantitatively and / or qualitatively equal to the composition for the layer C1 or quantitatively and / or qualitatively equal to the composition for the layer A. This leads to a further reduction of the complexity in the manufacturing process and creates a dynamically suitable bond of adhesion.

Layer C

The layer C forms the so-called "outer cap" of the article. The layer C is formed in at least two layers, wherein in each case the inner part C1 and the outer part C2 of the layer C are each formed from an elastomer mixture. The elastomer blends for the layer C1 and the layer A can qualitatively and / or quantitatively be the same or different from each other.

It is preferred if the elastomer mixtures for the layer C1 and the layer A are qualitatively and quantitatively the same. The production technology is the easiest to implement without unnecessary additional effort. The elastomer mixture of the layer C1 is a vulcanizable, preferably thermoplastic-free, rubber mixture containing at least one rubber component as well as further mixing ingredients. Rubber components which may be mentioned in particular are: ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), nitrile rubber (NBR), (partially) hydrogenated nitrile rubber (HNBR), fluorinated rubber (FKM), chloroprene rubber. Rubber (CR), Natural Rubber (NR), Styrene Butadiene Rubber (SBR), Isoprene Rubber (IR), Butyl Rubber (IIR), Bromobutyl Rubber (BIIR), Chlorobutyl Rubber (CIIR), Brominated Copolymer of Isobutylene and Paramethylstyrene (BIMS) , Butadiene Rubber (BR), chlorinated polyethylene (CM), chlorosulfonated polyethylene (CSM), alkylated chlorosulfonated polyethylene (ACSM), polyepichlorohydrin (ECO), terpolymers of ECO with ethylene oxide and unsaturated monomers (ETER), ethylene-vinyl acetate rubber (EVA), Acrylate rubber (ACM), Ethylene acrylate rubber (AEM), Silicone rubber (MQ, VMQ, PVMQ, FVMQ), Fluorinated methyl silicone rubber (MFQ), Perfluorinated propylene rubber (FFPM), Perfluorocarbon rubber (FFKM), Polyurethane ( PU). The aforementioned types of rubber may be unblended. The use of a waste is possible.

Which type of rubber is preferred depends on the type of article. The usual compounding ingredients include at least one crosslinker or crosslinker system (crosslinker and accelerator). Additional compounding ingredients are usually still a filler and / or a processing aid and / or a plasticizer and / or an aging inhibitor and optionally further additives (for example color pigments, adhesion promoters, flame retardants, reinforcing fibers.

In this regard, reference is made to the general state of rubber mixing technology.

The elastomeric mixture of the layer C2 is at least one elastomeric mixture with fire-retardant and / or self-extinguishing and / or flame-retardant properties. In principle, all the elastomers already described above for the layer C1 can be used. However, the elastomers used are preferably ECO, ETER, NR, CSM, CPE, CR and / or silicone rubber, alone or in combination. The thickness of the layer C2 is preferably chosen so that it gives the article a sufficient fire protection. To further improve the fire protection behavior, the elastomeric mixture for the layer C1 and / or the elastomeric mixture for the layer C2 may contain metal particles, for example of aluminum in the form of aluminum flakes. This leads to a further reduction of the layer thickness and thus to a thinner overall article. Likewise, a coating based on at least one fluorine-containing elastomer for optimizing dynamic efficiency is conceivable.

The layer C2 may completely or partially cover the article. Partially means in this context that only certain, defined areas or sections of the article are provided with the situation C2. The elastomeric mixture of the layer C2 may further contain, in addition to additional Mischingingredienzien, as already described for the layer A and the layer C1, other ingredients that act fire retardant or at least complicate the flammability. These may be flame retardants such as stannates such as zinc stannate or zinc hydroxystannate, hydroxides such as magnesium hydroxide or aluminum hydroxide, cyanurates such as melamine cyanurate, borates such as zinc borate, phosphorus containing components such as resorcinol diphosphate or aromatic polyphosphates, nitrogen containing components such as ammonium phosphate, carbonates such as calcium carbonate or magnesium carbonate, expandable graphite or Intumeszenzgemische act. Intumescent mixtures expand to foams. They are used to protect combustible materials such as plastics or wood, but also steel, which loses its strength at elevated temperatures, against the effects of heat and fire. Optionally, even small amounts of antimony trioxide, in spite of the hazardous effect, can be used in combination with at least one of said flame retardants.

The flame retardants may each be used alone or in combination. Particularly preferred for optimizing the fire retardancy is the use of microglass and / or hollow glass microbeads, which are preferably prepared adhesion-friendly, and / or hollow plastic balls with a flexible polymer shell and / or reflective substances, such as. Metal particles, in particular of aluminum and / or brass. The glass microspheres and / or the hollow glass microspheres melt in the event of fire and form glassy, insulating layers. If hollow spheres are concerned, preferably hollow glass microspheres, in a preferred variant fire-retardant substances may be encapsulated in the hollow spheres themselves, which are liberated after the outer shell has melted and then additionally act as a fire retardant in concentrated form.

In particular, the plastic hollow spheres can be present in already expanded form and / or in expandable form.

In a preferred embodiment, expandable plastic hollow spheres are used. In the expandable plastic hollow spheres, a gas is encapsulated. When heat is applied, the gas pressure in the interior of the shell increases, which softens at the same time. The resulting volume increase leads to an increase in the layer thickness, which leads to a further insulating effect even before the actual fire. In addition, the microglass spheres and / or hollow microglass spheres and / or hollow plastic spheres may be coated with at least one metal, for example aluminum. As a result, the effectiveness of the thermal insulation is additionally increased.

Layer D

The layer D consists of a woven or knitted or knitted fabric which is embedded in the outer layer C. The layer D is thus located between the layers C1 and C2. This is preferably a woven or knitted fabric in which the two sides can each be equipped with at least one adhesion promoter depending on the embodiment and application. The adhesion promoter may be resorcinol formaldehyde latex, a solution based on dinitrosobenzene, silane or a coupling agent based on at least one rubber.

Both sides can be equipped with the same bonding agent or with different ones.

In a particularly preferred embodiment, the fabric is a bi-stretch fabric which can be stretched horizontally and vertically, i. has a high elastic content in the warp and weft directions. The bi-stretch fabric has an extensibility of greater than 50%, preferably greater than 250%, in the warp direction and in the weft direction.

In order to achieve the extensibility in the different directions, preferably in the warp direction and in the weft direction in each case a sufficient amount, preferably 5 to 50 wt .-% of elastane present. The stretching in both directions but can also by appropriate textile manufacturing technologies such. Ex. To apply as little tension as possible when winding the freshly woven textile web obtained.

By using a bi-stretch fabric with the advantageous property of all-direction compliance, it is avoided that in the vulcanization process, elastomer blend during the embossing phase, i. Forming phase, so to speak pushed away.

As materials for the fabric, preferably the bi-stretch fabric, or knitted or knitted fabric, all natural and synthetic materials known to those skilled in the art may be used.

Synthetic materials are in particular synthetic polymers, such as polyacrylonitrile, polypropylene, polyester, polyamide, polyurethane, polyphenylene sulfide, polyoxadiazole, aramids, such as p-aramid, m-aramid or co-poly para aramid, polyimide, polyetherimide, polyetheretherketone, polyethylene 2,6-naphthalate, polyphenylene, polyphenylene oxide, polyphenylene sulfide, polyphenylene ethers, polybenzoxazoles, polyvinyl alcohol in question. The natural materials may be rock wool or asbestos, or cotton, flax or hemp, or wool or silk. Inorganic materials such as glass, ceramics, carbon (carbon), metal or rock, such as basalt, are also conceivable.

It is advantageous if a hybrid material of cotton, polyamide or polyester and elastane, with a cotton-dominating side and a polyamide or polyester-dominating side is used for the fabric, in particular the bi-stretch fabric, and / or the knitted fabric ,

In such a combination can be made of this fabric, knitted or knitted fabric prior to the manufacture of the article, a shell according to the required article diameter, the seams of this shell can be welded. The cotton content delays in the event of smoke or fire, the so-called "pop out", i. the breakthrough of the lower, more flammable layers to the heat-exposed surface, the due to the heat optionally molten layer B because the cotton content itself can not melt. This leads to a significantly improved fire protection behavior.

Particularly good fire protection properties are particularly evident when using a bi-stretch material based on aramid and elastane.

Layer E

The further layer E is based on at least one thermoplastic and is preferably located on the side of the layer D facing layer C2. Thermoplastics may be, for example, polyolefin, in particular polyethylene (PE), such as LD-PE, LLD-PE, UHMW. PE, or polypropylene (PP), polystyrene (PS), polyamide (PA), for example PA6 or PA6.6, polyester, for example PET, PEN or PBT. The layer E is formed in a preferred embodiment as a film. The use of PE film has proven particularly suitable, since it forms a particularly good adhesion composite, in particular in the case of peroxide-crosslinking elastomer mixtures, and thus, if appropriate, it is possible to dispense with further adhesion promoters. Depending on the nature of the article and the nature of the other layers, the layer E is particularly good adhesion. It can be applied to the article blank with the help of a heat radiator and pressure.

Layer G

The layer G of a woven, knitted or knitted fabric may additionally be on the outer layer C. This is preferably a fabric of warp and weft, particularly preferably a bi-stretch fabric, as has already been described for the layer D. The layer G can significantly reduce the flow of the elastomeric mixture of the layer C2 under pressure, sometimes even completely prevent. In addition, the other layers of the article are supported by the layer G, so that possibly occurring low adhesion detachment can be tolerated. Advantageously, the coefficient of friction of the surface of the article is additionally reduced by the layer G, resulting in a lesser article abrasion. The layer G may contain metal particles, for example aluminum in the form of aluminum flakes. The heat reflection of the metal particles leads to a further optimization of the fire protection behavior. Likewise, a coating based on at least one fluorine-containing elastomer, such as, for example, FKM or PTFE, is conceivable for optimizing the abrasion behavior.

The layers shown are combined according to one of the abovementioned variants 1 to 5 before or during the blank production, ie before the actual vulcanization process. In the first phase of vulcanization, the so-called flow or Ausformphase, thus, the various layers can flow well together, which has a positive effect on the adhesion of the layers with each other. An additional and costly second vulcanization process is not required.

The article is preferably an air spring bellows, a metal-rubber element, a vibration damper or a damping element of a bearing, a bush or a laminated spring or cone spring. The article can also be a tubular body. Tubular bodies are, for example, conveying hoses of all types, air bellows (cross-layer bellows, axial bellows) and compensators in various designs (for example torsion compensator, lateral compensator). Likewise, the article may be a drive belt.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2014/019008 A1 [0006, 0007]
• EP 2196492 B1 [0006, 0007]

Cited non-patent literature

• EN 45545 [0004]
• EN 45545 [0008]

Claims (6)

Article with a single- or multilayer main body with elastic properties, characterized in that the outer layer C consists of at least one first layer C1 and another layer C2 and each layer is formed in each case from an elastomer mixture, wherein in this outer layer C at least one Layer D is embedded from a woven or knitted fabric or knitted fabric between the first layer C1 and the further layer C2. Article according to claim 1, characterized in that the layer D consists of a bi-stretch fabric. Article according to one of claims 1 or 2, characterized in that the article still contains a further layer E. Article according to claim 3, characterized in that the further layer E is between the layer D and the layer C2. Article according to claim 3 or 4, characterized in that the further layer E is a film of polyethylene. Article according to one of claims 1 to 5, characterized in that it is an air spring bellows, a metal-rubber element, a vibration damper, a damping element of a bearing, a bush or a laminated spring or cone spring, a tubular body or a drive belt ,

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